MOSFET devices are widely used in DC/DC power systems as switches. In a buck circuit, as shown in FIG. 1, the high side MOSFET M1 and the low side MOSFET M2 are both OFF during a switching transition in order to prevent MOSFET damage under high current. So a fixed dead time is adopted in the circuit during which both of the high side MOSFET and the low side MOSFET are OFF. During this dead time, output current required by load RL flows through the body diode D0 of the low side MOSFET M2. However, the power consumption of the body diode D0 during forward conduction is high since the forward built-in voltage of the P-N junction of the diode D0 is around 0.7V. Also, the P-N junction of the diode D0 typically has bad reverse recovery characteristics since both holes and electrons participate in forward conduction.
Schottky diodes have much lower forward built-in voltage than that of the P-N junction diodes due to the metal-semiconductor contact, commonly referred to as the Schottky contact. So Schottky diodes consume less power than P-N junction diodes during forward conduction. Also, Schottky diodes have better reverse recovery characteristics than P-N junction diodes by having faster reverse recovery speed. Thus, it is desired for techniques to integrate a MOSFET and a Schottky diode in a monolithic semiconductor die.